Segmented couplings for pipes are well known in the art, and comprise two or more coupling segments each having a recess for the reception of a sealing gasket adapted to extend over the adjacent ends of a pair of pipes, and which are to be compressed by the coupling segments into sealing relation with the external peripheries of the respective pipes.
Each such coupling segment intended to couple the ends of grooved pipe has radially inwardly extending keys at its opposite axial sides, the keys being for reception in grooves in the respective pipe ends to perform the required mechanical interconnection between the pipes.
The coupling segments are drawn towards each other by traction bolts which extend through radially outwardly extending bolting pads at the respective opposite ends of the coupling segments. In this manner, the end faces of the coupling segments are drawn towards each other for them to clamp onto each other in the case of a “flexible” coupling, or, for the coupling segments to clamp directly onto the pipe exterior in the case of a “rigid” coupling. A “flexible” coupling is well known as one which will permit relative movement of the pipes to limited extents and the angling of the axis of one of the pipes relative to the other, whereas a “rigid” coupling is one which will immobilize the pipes against any such movements. Typical of such flexible couplings are those shown in U.S. Pat. No. 3,189,969 assigned to the assignee of the present application whose teachings are incorporated by reference herein, as well as the styles 75, 77, 72, and 750 couplings available from Victaulic Company of America, Easton, Pa. Similarly, typical of such rigid couplings are those shown in U.S. Pat. No. 4,639,020, assigned to the assignee of the present invention whose teachings are incorporated by reference therein, as well as the style 07 and 005 couplings available from the Victaulic Company of America.
Segmented pipe couplings are also known for the connection to pipes which do not contain a groove at their connection locations. Such commercially available couplings include: the style 90 and 99 plain pipe end coupling; and style 920 and 929 mechanical T couplings; all available from the Victaulic Company of America.
The aforementioned segmented pipe couplings are commercially available in a successive series of seriatim increasingly sized couplings, which are naturally configured to mate with similarly increased sized pipes.
Through inadvertence it is quite possible for a workman to incorrectly receive and connect two different sized arcuate coupling segments which are relatively close in size to each other. As the incorrectly matched coupling segments are tightened about the pipe end, as by tightening their traction bolts, they will not quite match up and form a circle about their inner diameter, against the exterior, and, in the case of a grooved type coupling, within the peripheral groove of the outer circumference of the pipe ends. Further the outboard corners or surfaces of the improperly mismatched segments of different sizes will not line up evenly. This misalignment, in relatively close size coupling segments (e.g., in the order between one-sixteenth to one-quarter of an inch of each other) is oftentimes difficult to readily visually perceive. Thus the worker may in such situations mismatch the individual coupling segments connected about the pipes being connected thereby, without readily realizing that a mismatch has occurred. This results in less than optimum sealing engagement between the pipe ends. Accordingly it is desirable to prevent such an inadvertent mismatch of the individual coupling segments, while providing a segmented pipe coupling having all the other advantages of presently available segmented pipe couplings, such as typically shown in aforementioned U.S. Pat. Nos. 3,189,969 and 4,639,020 and available from Victaulic commercial styles 75, 77, 07, 005, 90, 99, 72, 750, 920, or 929. Further it is desirable to prevent such an inadvertent mismatch by a simple modification of the presently existing coupling segments, which can be accomplished in a low cost manner, and will provide the workman with a readily visual indication that a mismatch is being attempted between closely sized coupling segments.